Smartwatch Study Finds Older Adults Can Sense Their Own Mental Decline in Daily Life

Four times a day for a week, a smartwatch on the wrist of an older adult buzzed with the same request: how sharp do you feel right now, and what is your mood? Once the answers were logged, the watch offered a brief test of processing speed and attention. That routine, repeated across 62 participants, is the core of a University of California, Davis study that suggests older adults may be better judges of their own moment-to-moment mental sharpness than scientists once assumed.

All 62 participants had scored within normal ranges on standard cognitive tests. The researchers accounted for age, mood and time of day. What emerged was a pattern within each person: when someone rated their sharpness below their own average, their performance on the objective tasks also tended to be lower. Both the perceived sharpness and the measured performance tended to slip later in the day. The work was published in Neuropsychology, a journal of the American Psychological Association.

The design departs from the usual approach. When patients raise concerns about their thinking, doctors typically depend on their recollection of past events and test them in an office, sometimes on a day when they are feeling better. Sarah Tomaszewski Farias, a study author and professor of neurology at UC Davis, said researchers and clinicians traditionally ask people to assess how their cognition has been over the past year, and those answers can be colored by recall bias. Asking repeatedly about the present moment could sidestep some of that. She also noted there are many open questions about how best to measure such complaints. Brandon Gavett, the study's first author, put it plainly: measuring change in a person's cognitive functioning is really hard.

There has long been skepticism that people can judge their own cognition, and mood is a central complication. Depression can shape how people evaluate their memory and abilities, and earlier research has linked subjective cognitive concerns with depression. Farias said one of the study's most encouraging findings was that the connection between perceived sharpness and objective performance did not appear to be explained by mood. She called that one of the aspects that surprised her most.

Heather Snyder, senior vice president of medical and scientific relations at the Alzheimer's Association, was not involved in the research. She described it as an interesting step toward understanding whether people's perceptions could give researchers additional information about cognitive health. "Our perceptions are sometimes the first indicator," she said. Snyder placed the study within a growing body of work on whether everyday technology can pick up subtle cognitive changes, noting that researchers are also using wearables to study speech and patterns of activity.

The appeal is the chance to measure outside a clinic. A traditional assessment captures performance at one point, often in a quiet, controlled room. A wearable could in theory gather many observations while a person cooks dinner, runs errands or goes about the rest of the day. Gavett said the findings offer a new way to bring people's own sense of whether their thinking is better or worse than normal into that picture.

The approach has practical limits. Gavett said some older adults may not want to wear the devices or be continuously prompted, and users must tolerate the interruptions and remember to charge them.

He was also direct about what a week of data cannot do: it will not tell anyone whether they are developing dementia. Scientists still need to learn whether patterns gathered over months or years can predict later cognitive impairment, and Gavett said researchers may need to follow people for that long to see whether the changes carry meaningful information about the risk of larger decline. Farias said that is now one of the biggest questions the team faces.

The next step, the researchers say, is to keep testing such approaches in clinical trials before moving to larger populations and judging how reliably they detect meaningful change. "Moving in the right direction to get people help for dementia as early as possible is the goal," Gavett said.